To write or not to write

So I've pondered this very question so many times - the debate inside my head is pretty simplistic actually.  If I begin to write, will I be able to stop and start - so many times when the thoughts are flowing, it's hard to put down the keyboard or close the notebook until there is more time.  But even more of a question - if I write and I face failure, I'd never try again.  Failure is not one of my strong points.  I anxiously await it and when it happens, I'm deflated to the lowest level possible.

So the question still lies - do I commit to begin on this journey, keep pondering the thought or say - not going to happen.